Musical instrument



Feb. 6, 1945. KEALOHA 2,368,842

MUS I CAL INSTRUMENT Filed Aug. 1, 1941 j gaiz INVENTOR. Ylan/ Jfi.Jniealohw /o I ATTO EY Patented Feb. 6, 1545 UNITED STATES PATENT OFFICEMUSICAL INSTRUMENT Ylan K. Kealoha, New York, N. Y.

Application August 1, 1941, Serial No. 405,015

7 Claims.

This invention relates to a musical instrument of the reed type, andmore particularly to a means and a method of providing for thetranslation of the vibration of the reed or of each reed where aplurality are present as in th accordion, into electrical impulses whichmay be amplified in any well known manner, so that when the instrumentis played with the amplifying means in use, the volume will be greatlyincreased.

It is among the objects of the invention to bring out the pleasingtimbre of a reed instrument such as an accordion by the fullreproduction of all overtones or harmonics which are present inconjunction with the fundamental vibration of the reed. Methods heretoprovided for the electrical amplification of the sounds generated by thereeds have not been fully satisfactory, due to th inability to pickupand reproduce all of these harmonics or overtones in addition to thefundamental vibration.

It is among the objects of the present invention to provide anelectrical pickup for a reed instrument which will reproduce the tonesof the vibrating reeds throughout their full range and with highfidelity.

It is a further object of the present invention to provide an electricalpickup of such nature and arrangement that the high tones produced bythe small reeds and the low tones produced by the larger reeds will beamplified in their true intensities so that neither the high notes northe low notes will be suppressed or weakened relative to the other, tothe end that all of the tones will be reproduced with greatly increasedintensity but that all will bear the same relative intensities that theypossess when the electrical amplification is not used.

In prior attempts to provide an electric pickup for accordionsconsiderable difficulty has been encountered due to the large number ofreeds involved, and the relatively close spacing of the same in theinstrument. This spacing is such, and the surrounding casing soconfined, that there is no room for the introduction of electricalequipment requiring any material amount of space.

It is among the objects of this invention to provide an electricalpickup which involves no material increase in the weight of theaccordion and which requires no increase in the space surrounding thewind box, but can be applied to accordions as at present constructed.

. Attempts have heretofore been made to over-v come some of theabove-mentioned difllculties between the reed and the plate.

and provide an electro-static pickup by means of a plate mountedadjacent to and in a plane parallel with the vibrating reeds. This plateis connected to one source of electrical potential or to ground whilethe reeds are connected to another and different potential. In suchconstructions, the charged plate is necessarily mounted at a suflicientdistance from the reeds to permit the same to vibrate freely. Thecapacity of the condenser so formed is, therefore, limited due to thedistance between the plate and the reed.

It is primarily the object of the present invention to provide aconstruction in which the plate upon which the reed is mounted, or aportion thereof, is utilized as on of a pair of condenser plates, whilethe vibrating reed itself acts as the other. The small clearance betweenthe plate and the reed, which is normally provided to permit the freevibration of the reed into and out of the usual perforations in theplate, is thus the limit of the distance between the plate and the reedand the determining factor in the condensereffect obtainable for anygiven difference in electrical potential.

It will be understood that the perforations in the plate adjacent whichthe reeds are mounted and through which they vibrate, are tapered towardthe reeds and it is necessary that the clearance between the plate andthe reed be very small, normally or the order of 0.001 to 0.0015 of aninch to avoid any unnecessary air leakage In the course of the vibrationof the reed this clearance is, of course, increased as the reed movesinto the tapered perforation. This small normal clearance may besomewhat enlarged for the purpose of electrification in order that asufiicient clearance may be provided between the reed and oppositelycharged plate to the end that leakage of electrical current therebetweenwill be avoided. However, by the provision of adequate insulation thearrangement of which will be hereinafte descr bed, the necessity for anyalteration in the clearance between the reed and the plate may belargely avoided.

The above and other objects of the present invention will be apparent tothose skilled in the art from a consideration of the following detaileddescription taken in conjunction with the accompanying drawing in which:

Figure 1 represents a top plan view of a reed plate, having a pair ofreeds mounted thereon in the usual manner, but having a portion thereofelectrically insulated from the remainder of the plate and from thereeds in accordance with this invention.

Figure 2 represents a longitudinal section taken on the line 2-2 ofFigure 1.

Figure 3 is a transverse section taken upon line 3-4 of Figure 1.

Figure 4 is avie'w corresponding to Figure 1 of a modified form of theinvention.

Figure 5 is a section taken upon line 5-4 of Figure 4.

Figure 6 is a, transverse section taken on line 6-8 of Figure 4, andFigure 7 is a transverse section taken on line 1| of Figure 4.

Figure 8 is a view corresponding to Figure l of a further modified form.

Figure 9 is a longitudinal section taken on line 9-9 of Figure 8, andFigure 10 represents a transverse section taken upon line Iii-i0 ofFigure 9.

Referring to Figure 1, reference numeral I indicates one of the reedplates of an accordion. It will be understood that, except for thealterations hereinafter noted, this reed plate is of conventionalconstruction and that the remaining reed plates of the accordion, ofwhich there may be any number mounted upon the usual bridge block, aresubstantially identical in structure except for the size thereof whichwill vary from the high notes requiring relatively small reeds, to thelow notes requiring relatively large reeds. A pair of reed 2 and 3 aremounted in the usual manner on opposite sides of the plate I by means ofpins or rivets Land 5. As in conventional structures the reeds 2 and 3vibrate in and adjacent to oblong openings 6 and I provided in the platestructure I. As will be readily understood by those skilled in the art,a very small but uniform clearance i provided between the reeds 2 and 3,and the side walls of the openings 6 and 1. Between the two cut-outportions or perforations 6 and I a bar 8 of the original plate materialremains. In the normal structure, the center bar 8 is accordinglyintegral with the remaining portion of the plate structure I. Inaccordance with the present invention, however, a bore 9 is cut orPunched in the center bar 8 at a point adjacent the fixed ends of thereeds 2 and 3, and a similar bore III is cut or punched through thecenter bar 8 at a point adjacent the free ends of the reeds. Rod of hardinsulating material ii and I2, of such external diameter as to provide avery tight fit with the bores 9 and it) forced or drawn thereinto underconsiderable pressure. In order to increase the grip of the insulatingrods II and I2 upon the side walls of the bores 9 and I0 it ispreferable, though not essential, to provide the rods with crew threadedor corrugated surfaces which, when forced into bores having slightlyless diameter than the overall diameter of rod and thread, provide avery secure grip such that the rod cannot be subsequently removed by theapplication of any force to which the plate is likely to be subjectedwhile in use. After the rods H and i2 are securely in place, a thin cutI3 is made through the bar 8 to the rod lit at each ide thereof, andsimilar cut I4 are made through the bar 8 to the insulating rod [2.

By this operation the center bar 8 is entirely insulated from theremainder of the plate I without in any way disturbing its positionrelative thereto, and accordingly without disturbing the very smallclearance between the edges of the reeds 2 and 3 and the center bar. Thestructure remains entirely rigid. That is, the center bar I does nottend to slip into or out of its position but remains as fixed as it wasoriginally through all ordinary handling. The space formed by the cutsi3 and it forms a suitable insulating gap between the bar I and theremainder of the plate I. These gaps may be filled with insulatingmaterial if desired. A conducting pin II is provided in the center barI, and a similar conducting pin i8 is provided in the body portion ofthe plate I. It will thu be seen that when the conducting pin I5 isconnected to one pole of a source of current or positive potential, andthe remaining pin i6 is connected to the opposite pole of the samesource, or to ground the metallic reeds 2 and I, which are conductivelyconnected to the plate, will be at one potential, while the center bar 8is at a different potential. The structure, therefore, forms a condenserhaving center bar 8 forming one plate thereof positioned betweenoppositely charged plates formed by reeds 2 and 3. Vibration of eitherof the reeds 2 and I will vary the effective capacity of the condenserand since the condenser effect exists throughout the full length of thevibrating portion of the reed it will be seen that the variation incondenser effect will include both the fundamental vibration and allovertones.

It will be understood that the electrical connection to the pin I 5 willpreferably be in the form of a bus-bar which extends across a pluralityofthe plates I, and connects all, or any desired number of similar bars8 of any set to the same source of potential, while the pin I6 islikewise connected to a similar bus-bar connecting all, or any desirednumber of the plates I to a source of negative potential, or to ground.Thus the only increase in weight in the accordion to which the inventionis applied is the negligible weight of the two bus-bars forming the twoelectrical connections for all of the plates.

While the gap or clearance between the reeds 2 and 3, and the bar 8 maybe relied upon to provide a sufficient insulating gap between the reedsand the bar 8, it is sometimes desirable to apply a thin coating ofinsulating material H on the ide walls of the bar 8 adjacent the reeds 2and 3 to insure that any dust particles coming between reeds and the barwill not provide a direct conducting path therebetween. Since, in thisform of the invention only the bar 8 is at a different potential fromthe reeds it serves no electrical function to apply insulation to theother side walls of the openings 6 and 1, however, since in the procesof manufacture the insulation is conveniently applied with a brush itmay be imultaneously applied to both sides of the openings 6 and 1thereby insuring that the clearance between the reed and the opening isthe same upon both sides of the reed.

Referring to the modified form of the invention as shown in Figures 4,5, 6 and 7, the reed plate 2| carries the reeds 22 and 23 which aremounted upon opposite sides thereof, and insulated therefrom by thesheets of insulating materia1 24 and 25, which, for the sake ofconvenience of construction and for the purpose of providing insulationbetween the reed and the side wall of the perforation along the line ofthe least clearance there-between, may cover the entire surface area ofeach face of the plate or at least that portion thereof adjacent theperforations. As shown, the reeds are attached rigidly to the plate bymeans of screw bolts 26 and 21 of insulating material. It will beunderstood that any suitable fastening means, such as rivets or pins,

may be used for this purpose, provided the same are adequately insulatedto avoid any electrical connection between the reeds and the plate. Whenso constructed the free ends of the reeds 22 and 23 may vibrate freelyinto the openings or oblong perforations 28 and 29 of the plate 2| fromwhich they may be insulated by a thin coating of insulating material 30,sprayed or otherwise formed on the internal walls of the openings forthe purpose of preventing any electrical connection between the edges ofthe reeds 22 and 23 and the reed plate 2!. However, since there isnormally a slight clearance between the edges of the reeds 22 and 23 andthe internal wall of the opening as the reed vibrate therein, it ispossible to rely merely upon this air gap without insulation of the sidewalls of the openings, provided the difference in electrical potentialbetween the plate 2! and the reeds 22 and 23 is not too great.

The reeds 22 and 23 are connected to a suitable source of electricalpotential by metallic tabs 3|, which have a suitable surface area incontact with the reeds preferably at the point of fixation thereof. Eachof the tabs 3! is connected to a suitable bus-bar common to all of thereeds. Plate 2i is connected by suitable pin 32 to a different source ofelectrical potential or to ground by way of a suitable bus-bar common toall of the plates.

- The operation of the above-described modification will be obvious fromthe consideration of the operation on the form previously described inconnection with Figures 1, 2 and 3 and, obviously, this form willprovide a greater condenser effect, for the same difference in potentialbetween the plate and the reeds, than the form shown in Figure l.

The form shown in Figures 8, 9 and is similar in many respects to theform shown in Figure 4 et seq. except that the plate 33 is provided witha wedge-shaped portion, 34 and 35, surrounding the free ends of thereeds 36 and 31, so that the ends of the reeds which move through agreater distance than the mid portion of the reeds, are throughout theirperiod of vibration in close proximity to the oppositely charged surfacearea, the same as exists when the reed vibrates into the opening orperforations 38 and 39, as when it is outside or beyond thisopening--this arrangement insures a somewhat greater capacity eflect inthe outermost position of the vibrating reed. Having thus described theinvention I claim: 1 An electrical pick-up for a musical instrument ofthe type including a vibrating reed mounted upon a. metallic plate,meanswhereby said read is electrically insulated from a portion of saidplate and means connecting said reed and said portion of said plate todifferent electrical potentials in an amplifying circuit.

2. In a musical instrument. a condenser, said condenser comprising areed secured at one end to a metallic plate, the remaining portion ofthe reed extending contiguous to the plate and being free forunrestricted vibration, said reed forming one electrode of the condenserand said plate forming the opposite electrode of the condenser.

3. In a musical instrument of the type having a plurality of vibratingreeds rigidly attached at one end thereof to a metallic plate, means forelectrically insulating said reeds from said plate and means forconnecting said reeds and said plate to sources of different electricalpotentials in an amplifying circuit.

4. In a musical instrument of the type having a plurality ofvibratingreeds rigidly attached to the opposite faces of a perforatedplate, means for electrically insulating a portion of said plate betweensaid perforations from the remainder thereof and means for connectingthe two portions of the plate thus insulated from each other to sourcesof different electrical potentials in an amplifying circuit.

5. In a musical instrument of the type having a vibrating reed rigidlyattached to a face of a perforated, metallic plate and having its otherend free for vibration into said perforation, means comprising a thinsheet of insulating material between said plate and said reed forelectrically insulating the same, said sheet extending over the surfaceof said plate adjacent the edge of said perforation, and means forconnecting said reed and said plateto different electrical potentials inan amplifying circuit.

6. An electrical pick up for a musical instrument of the reed type,including in combination. a metallic plate having a perforated portion,a metallic reed rigidly attached at one end thereof to a face of saidplate and having its other end free for vibration into and adjacent saidperforated portion, means for electrically insulating said reed fromsaid plate, and means for connecting said reed and said plate to sourcesof different electrical potentials in an amplifying circuit, wherebysaid reed forms one electrode of an electrical condenser and said plateforms the oppositep electrode of said condenser.

7. In a musical instrument, a metallic reed mounted for vibration, ametallic member adjacent said reed and extending along the lengththereof and in the same general plane as that of said reed when the sameis in its stationary position, means for electrically insulating saidreed from said member and means for connecting said reed and said memberto different electrical potentials in an amplifying circuit, wherebysaid reed forms one electrode of an electrical condenser and said memberforms the opposite electrode of said condenser.

K. KEALOHA.

